What helped me when I was in school was not eating till after I studied and I spent a few hours studying too. Not just a few minutes here and a few minutes there. Sit down in a quiet area nothing playing in the background to distract you and study. Don't stop for anything unless its the bathroom break. After your done studying go eat something and fall asleep. What also helped me was writing all the information down by hand because the more you write it the better you will remember it. Take notes as your teacher is going over something and also pay close attention. Just reading is not enough keep that in mind.